Curtailment Strategies

The SMART System is designed to facilitate acoustically triggered curtailment (ATC) of wind turbines. ATC is the practice of slowing or stopping a wind turbine in response to detected bat vocalizations and activity levels.

Wind turbine curtailment strategies can be distinguished by what kinds of information they take into account:

Blanket Curtailment
Blanket curtailment, sometimes called simply curtailment, means keeping wind turbines inactive during times of the day and days of the year when bats are expected to be active. This strategy does not incorporate real-time measurements of bat activity or environmental conditions.
Operational Curtailment
Operational curtailment involves taking real-time wind speed measurements into account, in addition to date and time. Bats tend to be most active when wind speeds are low, so the turbine is shut down when wind speeds are slower than a set threshold.
Smart Curtailment
Smart curtailment goes beyond operational curtailment by accounting for environmental factors beyond wind speed, such as precipitation and temperature. The turbine is shut down during environmental conditions associated with bat activity, but real-time bat activity measurements are not directly taken into account.

One use case for the SMART System is to record bat activity prior to a turbine's construction in order to build a model correlating bat activity with environmental conditions. The SMART Controller's connectivity features and the robustness and redundancy of the SMART MIC-1 make the system well suited for installation on a wind turbine or meteorological tower, regardless of the specific goal. However, SMART has additional features that can grant your curtailment program an additional level of sophistication.

Acoustically Triggered Curtailment

SMART is designed to let you use real-time measurements of bat activity to inform your curtailment logic–not just past measurements. Implementations can vary, but this type of ATC generally follows this sequence:

  1. As the SMART microphones detect and record nearby bat echolocation calls, the SMART System measures the characteristics of each pulse and average measurements for pulses in a given sequence.
  2. These call measurements are processed through user-designed logic to distinguish bat calls from mechanical noise.
  3. When the number of bat calls in any set of criteria meets a user-specified threshold, a corresponding alarm is raised. The SMART can signal eight alarms based on individual pulse measurements and eight alarms based on average measurements of pulse sequences.
  4. The status of each of the 16 possible alarms is communicated to the turbine control or SCADA system. The SMART supports multiple communication protocols for this purpose.
  5. The turbine control system processes SMART's alarm signals, along with other relevant data, and determines whether to shut down or slow a turbine.